The present invention relates to a method, a device and a system in a vehicle for communicating a deviation of a measured actual vehicle parameter value from its corresponding predetermined value to a driver as well as a vehicle comprising such a device and such a system, and a computer readable medium comprising a computer program for performing such a method.
Modern vehicles comprise a plurality of devices and systems for communicating different values or warnings to a driver. Especially, the application of different driver assistance systems, as e.g. an ADAS system (advanced driver assistance system) are intended to assist the driver by providing a plurality of additional information, the driver is often not even able to be aware of. For example, the ADAS system provides data of a travelled road, e.g. whether the vehicle is approaching a curve or bend, or what kind of road is travelled (highway etc.). Even additional information on the road pavement can be communicated to the driver. Often the vehicle is also equipped with infra-red cameras and/or wireless communication possibilities gathering information provided on the road for example by sign posts or by remote navigation system providers. Also other environmental conditions, such as rain, wind, darkness, can be taken into account and be communicated to the driver. But also “simple” information, as for example the fact that a driver is exceeding a speed limit, can be communicated. Mostly, this information is communicated by warnings in order to attract the driver's attention.
From the article of Kumar, M., Kim, T., “Dynamic Speedometer: Dashboard redesign to discourage drivers from speeding”, CHI, Apr. 2-7, 2005, Portland, Oreg., USA (see also: hci.stanford.edu/research/speedometer/LBR-197-kumar.pdf), for example a speedometer is known which is adapted to visually distinguish the regions of the speedometer which are higher than a current speed limit. As the speed limit changes, the visualization on the display is updated accordingly. This relieves the driver of the task of waiting/searching for speed limit signs on the road to determine the current speed limit in effect. The disclosed speedometer can be instrumented to provide visual cues such as making the speedometer needle glow, changing the colour/illumination of the over-the-speed limit region of the speedometer, or changing the background of the dial itself when the driver exceeds a certain threshold over the speed limit. Additionally, an audio notification such as beeps of varying frequency and amplitude can be used, wherein the variation can be dependent on the excess over the speed.
The additional information provided to the driver is supposed to increase the safety of driver, passenger(s) and outside traffic participants, since knowing the vehicle's current situation may allow the driver/vehicle to prevent accidents. On the other hand the plurality of information and warnings can easily distract the driver's attention or even result in a complete neglect.
It is therefore desirable to provide a communication method, device and system which communicate information about vehicle related parameters to the driver of said vehicle and support the driver in driving said vehicle without the need of direct interaction.
According to aspects of the present invention, a communication method, a device and a system, as well as a vehicle and a computer and computer program product are provided.
An aspect of the invention is based on the idea that by (i) determining an amount of a deviation of an measured actual vehicle parameter value from its corresponding predetermined value, (ii) colour-coding said determined amount of deviation and (iii) communicating said amount of deviation to the driver by using said color code, the driver can be guided to the correct drive behaviour without direct warning.
For determining the amount of deviation, according to the invention it is preferred to use an algorithm which is based on a weighting function and which combines the difference between the measured actual value of the vehicle parameter and its corresponding predetermined value with a first weighting factor. The weighting factor is related to the vehicle parameter and can advantageously be at least one of (i) an additional vehicle parameter, e.g. weight, payload, braking power, and/or (ii) an environmental parameter, such as road conditions/characteristics, weather, distance to an obstacle etc. The result is color coded communicated to the driver and also gives an information about a necessity to act.
The predetermined value itself can be, as a preferred embodiment of the invention shows, a target value the measured actual vehicle parameter should have at a predetermined target time and/or a predetermined target location, and can also be weighted with a second weighting factor. Since the second weighting factor is also related to at least one additional vehicle parameter e.g. weight, payload, braking power, and/or at least one environmental parameter, such as road conditions/characteristics, weather, distance to an obstacle etc. the target value changes correspondingly.
According to another preferred embodiment, the predetermined target value is a calculated optimal value for the measured actual vehicle parameter at the time and/or the location of the actual measurement. The optimal value can be determined e.g. by a nominal function, such as an interpolation or an extrapolation between/from the measured actual vehicle parameter measured at an initial time and/or an initial location and/to a target value the measured vehicle parameter should have at a target time and/or a target location. The calculation of the optimal value can also take into account a second weighting factor which in turn is related to another vehicle parameter e.g. weight, payload, braking power, and/or an environmental parameter, such as road conditions/characteristics, weather, distance to an obstacle etc.
Consequently, the color coded information of the deviation of the measured actual vehicle parameter value and the optimal value can guide the driver to the correct driving behaviour.
In other words, if the actual measured value is the optimal value for the location the value is measured, the method according to the invention will not show any color coded information at all. Only, if the actual measured value of the vehicle parameter deviates from the calculated optimal value for the corresponding measurement location, the method according to the invention will show any colour-coded information to the driver.
Since, as explained above, this difference between the actual measured vehicle parameter value and the predetermined vehicle parameter value is a continuous function in time which usually will increase or decrease having positive values (in case the measured actual vehicle parameter value exceeds its predetermined value) or negative values (in case the measured actual vehicle parameter value is below its predetermined value) or zero (in case the measured actual vehicle parameter value is identical with its predetermined value) the corresponding color code will change continuously as well.
Preferably, the color code is communicated to the driver's peripheral vision so that the driver is not distracted from driving the vehicle by paying attention to a plurality of warnings. Especially, the communicated information can also be a combination of a plurality of system parameters without increasing the number of warnings.
The communication to the driver's peripheral vision can be achieved for instance by changing the color brightness, color saturation and/or color hue of a communication device, so that the communication device is more or less visible to the driver whereby also a necessity to react is communicated.
This continuous change causes fading in/fading out effects of the color coded information signal shown to the driver on the communication device. If he currently does not drive the vehicle in accordance with the correct way (i.e. the correct vehicle speed as a function of time) the warning signal according to the invention will be shown causing him to react. If he, as a preferred embodiment of the invention shows, decelerates or accelerates the vehicle, as the case may be, towards the optimal speed or the target speed the color coded signal will gradually fade out (change in brightness towards lower brightness values) or change its color hue e.g. towards green, thereby indicating that the driver is moving towards the correct driving behaviour. If he, contrary to such behaviour, is accelerating or decelerating the vehicle, as the case may be, away from the optimal speed or the target speed the color coded signal will gradually-fade in -(change in brightness towards higher brightness values) or change its color hue e.g. towards red. If and as long as the actual current vehicle parameter is either above or below the optimal speed or target speed it may under special circumstances happen that the color coded signal will not change at all depending on the weighting factors used. Since the first and/or second weighting factor/s is/are dependent on at least one additional vehicle parameter e.g. weight, payload, braking power, and/or at least one environmental parameter, such as road conditions/characteristics, weather, distance to an obstacle etc., the color coded signal usually is different for different vehicles and/or different times and/or different situations.
It is also possible to use the invention for other vehicle parameters, as e.g. RPM (Revolutions Per Minute) or fuel consumption. Preferably, the vehicle parameter is related to parameters provided by a driver's assistance system, as for example an ADAS system, and/or by a remote system e.g. a customer defining the driving behaviour of his drivers, for example a recommendation for travelling along with a green wave.
The invention can advantageously be used for vehicle parameters which are suitable for being communicated by a gauge or a meter to the driver. The color coded can preferably be implemented by changing the illumination, e.g. the background light of the gauge/meter or by colouring the gauge's/meter's display. The illumination/colouring can be performed for example by the use of LED, or the speedometer itself is already designed as LCD panel.
Preferably, the color coded is provided by increasing/decreasing the brightness or hue of a color of e.g. of the gauge's/meter's background light. Dependent on the weighted amount of deviation and whether or not that weighted amount is increasing or decreasing over the time the background light is                fading in (i.e. gradually increasing its brightness, hue, or intensity or gradually changing its color for instance in a range from green over yellow to red or, alternatively, from normal display background light (or to a state without any background light-)-over yellow-to-red) or        fading out (i.e. gradually decreasing its brightness, hue, or intensity or gradually changing its color for instance in a range from red over yellow to green or, alternatively, from red over yellow to the normal background light (or to a state without any background light)) and is therefore recognizable by the driver's peripheral vision. It is therefore not recognized as “real” warning, and consequently the driver is not distracted by it. Because of the smooth fading in/fading out it is also possible to communicate the “warning” quite late without causing panic reactions by the driver. It also provides an easy retrofitting possibility for existing vehicles.        
According to a further preferred embodiment of the invention color hue, brightness and/or saturation are/is also adaptable to ambient light. This has the advantage that a deterioration of the visibility due to daylight or other bright ambient light or distracting reflections of the inventive communication device in a windscreen during night-time or driving in a tunnel can be reduced. Especially, since the peripheral vision of the driver is addressed, reduced visibility or distraction by reflections can result in a disregard of the information. Preferably, the adaptation can be performed manually or automatically. The actual ambient light can preferably be measured with the help of optical sensors.
According to another preferred embodiment, only a part of the gauge/meter is illuminated/coloured, particularly that part which exceeds/succeeds the predetermined value. That means for example for the above described embodiment of the bend speed warning that that part of the speedometer is coloured that is between the predetermined speed for the bend and the measured actual speed shown at the speedometer (exceeding the predetermined speed). The weighted amount of the deviation from the measured actual value and the predetermined value can then again be communicated by fading of the color brightness, saturation or hue. It is also possible to increase/decrease the illuminated/coloured part of the gauge/meter to indicate the amount of deviation.
Further advantages and preferred embodiments are defined by the description and/or the figures.